Turbine discs are rotatably mounted to a shaft of a conventional gas turbine. The turbine discs are capable of receiving e.g. the turbine blades. The turbine discs rotate with respect to stationary, non-movable turbine parts, so that the turbine discs need sealing and balancing arrangements in order to provide proper sealing and rotating characteristics.
Between movable parts, such as turbine discs, and stationary parts, such as the output pre-swirling device and the turbine housing a plurality of cavities exists. Between the movable parts and stationary parts a proper sealing is necessary. Therefore, in conventional gas turbines, the leakage reduction from of fluid inside a cavity may be controlled by the use of e.g. a single seal fin arrangement that is arranged at a predetermined location onto the conventional turbine disc.
Moreover, a balancing arrangement for balancing the movable part is necessary. This balancing arrangement may be achieved e.g. by the use of a balancing band at a predetermined location onto the turbine disc, in particular onto the opposite side of the turbine disc, where the single fin arrangement is located.
FIG. 4 shows such a conventional turbine disc arrangement. Onto a first surface of a conventional turbine disc 400 a conventional single sealing lip 401 is arranged and on the opposite side of the conventional turbine disc 400 a conventional balancing arrangement 402 is arranged.
U.S. Pat. No. 4,817,455 discloses a balancing arrangement for a gas turbine engine, wherein a snap ring is placed within a groove in a rotor disc of a rotor. In a spaced location with respect to the snap ring, a sealing arrangement may be attached to the rotor disc.
U.S. Pat. No. 4,926,710 discloses a method of balancing bladed gas turbine engine rotors. A balancing ring is mounted to a rotor disc between a snap ring and a lip of the turbine disc. At a spaced location with respect to the balancing ring, a labyrinth sealing for sealing the rotor disc is arranged.
U.S. Pat. No. 4,220,055 discloses a balancing device for balancing a rotor. Weights, in particular L-shaped weights, are arranged between a first turbine part and a rotatable second rotor part. At a spaced location with respect to the L-shaped weights, a labyrinth sealing arrangement is formed on the rotor disc.
U.S. Pat. No. 7,491,031 B2 discloses a balancing device of a turbo machine engine. To a flange of a turbine disc a sealing disc or a further disc is fixed by a bolt-nut connection. Between the bolt and the nut, a counterweight is attached. At a spaced location of the disc, labyrinth sealing elements may be formed.
In U.S. Pat. No. 3,985,465 a substantially radial outward surface of an axial extension of a compressor disc is used to hold balancing weights. This allows access to the balancing weights by an elongated tool from radially outwards via an access hole. The position of the balancing weights is near a wide passage in the main fluid path between a stator shroud and a rotor blade of the axial flow compressor. The wide passage specifically does not form a seal but may be present to divert fluid from the main fluid path to a secondary air system.
Thus, the sealing arrangement and the balancing arrangement in the conventional arrangement are functionally decoupled and have no interactions between each other.